QBE – a new compiler back end

QBE aims to be a pure C embeddable backend that provides 70% of the performance of advanced compilers in 10% of the code. Its small size serves both its aspirations of correctness and our ability to understand, fix, and improve it. It also serves its users by providing trivial integration and great flexibility.

http://c9x.me/compile/

>>12
It means that it only supports the reasonable subset. You can do an awful lot of shit in C that takes advantage of undefined behavior to hack together something that works but is buggy and exploitable as fuck. The goal is not to satisfy the whims over every currynigger who wants to implement the Seeples templating system with proprocessor hacks to automatically make tagged unions, but to make a compiler with consistent behavior that you know won't be doing stupid shit with your program at compile time.